Because the fish spends such a short time in the cooker, the first 30 minutes are spent developing flavor in the braising liquid.
You'll need a 3-quart slow cooker for this recipe.
Make Ahead: Leftover tapenade can be refrigerated for up to 1 week.
Servings: 4 - 6
- 1/4 cup no-salt-added vegetable broth (may substitute fish stock)
- 5 tablespoons extra-virgin olive oil, plus more for the spinach
- 1/4 cup dry white or rose wine
- 1/2 medium onion, finely chopped
- 6 dried bay leaves (may substitute 3 fresh bay leaves)
- 1/2 teaspoon kosher salt, plus more as needed
- Freshly ground black pepper
- 12 ounces fresh center-cut tuna, cut into thick steaks
- 2 cloves garlic, thinly sliced
- Grated zest of 1 orange
- 5 ounces pitted, mild green olives, such as Picholine or Lucques (about 3/4 cup)
- 5 ounces pitted, brine-cured black olives, such as Nicoise (about 3/4 cup)
- 1 teaspoon red or white wine vinegar
- 5 to 6 ounces fresh baby spinach
Combine the broth, 4 tablespoons of the oil, the wine, onion, bay leaves and salt in the slow cooker; season with pepper to taste. Stir, then cover and cook on LOW for 30 minutes. During this time, let the tuna steaks come to room temperature.
Add the tuna, turning to coat the pieces evenly. Cover and cook on LOW for 15 minutes; use a spatula to turn the steaks over, cover and cook for a total of up to 35 minutes, so the fish is opaque and firm (start checking after 25 minutes). Use a slotted spatula to transfer the fish to a cutting board or large plate, then use two forks to separate the pieces into large flakes. Cover loosely to keep warm. Discard the braising liquid.
While the fish is cooking, combine the garlic, orange zest, olives, vinegar and the remaining tablespoon of oil in a food processor. Pulse to form a thick puree. The yield is about 1 1/2 cups.
When ready to serve, toss the spinach in a mixing bowl with a little oil to lightly coat. Season with salt and pepper to taste. Divide among individual plates, creating a bed for the tuna. Distribute the fish evenly among the portions. Top with the tapenade. Serve at room temperature.
Adapted from Williams-Sonoma's "The New Slow Cooker: Comfort Classics Reinvented," by Brigit Binns (Weldon Owen, 2010).
Tested by Jim Webster.
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